Merge pull request #3 from abreslow/master

Fixes bugs and warnings.  Specific fixes include https://github.com/A…

benchmarking/Makefile

@@ -34,12 +34,20 @@
 
 
 ifndef CXX
-  CXX=g++ # Code uses GCC builtins.  I do not recommend changing the compiler.
+  CXX=g++ # Code uses GCC builtins.  I recommend using either g++ or clang++.  
+          # GCC's g++ is probably preferred since it appears to yield better 
+	  # throughput numbers.  However, the results are roughly comparable.
 endif
 
+# Comment the line below back in if you want to instrument the code with the 
+# sanitizer functionality
+#SANITIZE:=-fsanitize=address,undefined,leak
+
 OPT=-Ofast -march=native -mpopcnt 
 
-FLAGS:=-Wall -Winline -g -std=c++11 $(OPT)
+FLAGS:=-Wall -Winline -g -std=c++11 $(OPT) $(SANITIZE)
+
+# Need to routinely check for bugs with -fsanitize=address -fsanitize=undefined
 
 TARGETS=benchmark \
   benchmark_cf benchmark_mf \

bf.h

@@ -60,7 +60,7 @@ namespace BlockedBF{
     inline bool contains_and_update(const hash_t item){
       constexpr slot_type one = 1;
       constexpr slot_type slot_width_bits = sizeof(slot_type) * 8;
-      constexpr slot_type log2_slot_width = log2(slot_width_bits);
+      constexpr slot_type log2_slot_width = util::log2ceil(slot_width_bits);
       constexpr slot_type shift0 = 0;
       constexpr slot_type shift1 = log2_slot_width;
       constexpr slot_type shift2 = log2_slot_width * 2;

block.h

@@ -413,7 +413,6 @@ struct Block{ // Assuming block size is a multiple of atom_t's size in bytes
       memcpy(source_address, &item, field_width_bytes);
     }
 
-    __attribute__((optimize("unroll-loops")))
     INLINE void add_cross_left_displace(uint64_t raw_offset_bits, 
       uint64_t field_width_bits, uint64_t index, atom_t item){
       uint64_t global_index = index * field_width_bits + raw_offset_bits;

compressed_cuckoo_filter.h

@@ -457,7 +457,9 @@ namespace CompressedCuckoo{
     // Currently set to false because clear_swath hasn't been rigorously tested
     constexpr bool _only_clear_ota_and_fca = false;
     if(!_only_clear_ota_and_fca){ // Competitive with the code in the loop below
-      memset(storage, 0x0, allocation_size);
+      for(hash_t i = 0; i < total_blocks; i++){
+        storage[i] = block_t{}; 
+      }
       return storage;
     } // ELSE
     for(hash_t i = 0; i < total_blocks; i++){
@@ -496,6 +498,9 @@ namespace CompressedCuckoo{
 
       size_t allocation_size = sizeof(*_summed_counters) * 
         (_buckets_per_block + 1);
+      // Round allocation size up to a multiple of 64.
+      allocation_size = (allocation_size + g_cache_line_size_bytes - 1) & 
+        ~(g_cache_line_size_bytes - 1);
       _summed_counters = static_cast<decltype(_summed_counters)>(aligned_alloc(g_cache_line_size_bytes, allocation_size));
      // Memset not required, initialized by full_exclusive_scan 
 
@@ -665,8 +670,8 @@ namespace CompressedCuckoo{
     constexpr uint_fast8_t num_passes = util::log2ceil(_buckets_per_block);
     static_assert(_max_fingerprints_per_block > 0, "The number of fingerprints "
       "per block must be one or more.");
-    constexpr uint_fast8_t masked_count = static_cast<uint_fast8_t>(ceil(log2(
-      _max_fingerprints_per_block) / _fullness_counter_width)) - 1;
+    constexpr uint_fast8_t masked_count = static_cast<uint_fast8_t>(util::log2ceil(
+      _max_fingerprints_per_block) / _fullness_counter_width) - 1;
     for(int8_t i = 0; i < masked_count; i++){ // Masked to avoid overflows
       sum = (sum & _reduction_masks[i]) + ((sum >> (_fullness_counter_width << i)) & _reduction_masks[i]);
     }
@@ -730,8 +735,9 @@ namespace CompressedCuckoo{
   INLINE uint16_t exclusive_reduce_with_popcount128(const block_t& b, 
     uint8_t counter_index) const{
     constexpr __uint128_t one = 1;
-    const __uint128_t mask = (one << (_fullness_counter_width * counter_index)) 
-      - one;
+    // Thanks to @asl for the bugfix https://github.com/AMDComputeLibraries/morton_filter/issues/2#issuecomment-568480311 
+    const uint64_t shift = _fullness_counter_width * counter_index;
+    const __uint128_t mask = shift == 128 ? __uint128_t(-1) : (one << shift) - one;
     uint8_t sum = 0u;
     __uint128_t counters;
     memcpy(&counters, &b, sizeof(__uint128_t));
@@ -1192,12 +1198,12 @@ namespace CompressedCuckoo{
 
   // Reports the C parameter from the VLDB'18 paper.  This is the ratio of physical slots in the FSA
   // to logical slots per block.
-  constexpr double report_compression_ratio(){
+  constexpr double report_compression_ratio() const{
     return static_cast<double>(_max_fingerprints_per_block) / (_buckets_per_block * _slots_per_bucket);
   }
 
   // This is the $\alpha_C$ term in the paper.
-  inline double report_block_occupancy(){
+  inline double report_block_occupancy() const{
     uint64_t full_slots_count = 0;
     for(uint64_t block_id = 0; block_id < _total_blocks; block_id++){
       full_slots_count += get_bucket_start_index(block_id, _buckets_per_block); 
@@ -1208,7 +1214,7 @@ namespace CompressedCuckoo{
   // Methods specific to Morton filters
 
   // Reports what fraction of the bits of the Overflow Tracking Array are set
-  double report_ota_occupancy(){
+  double report_ota_occupancy() const{
     uint64_t set_bit_count = 0;
     if(_morton_filter_functionality_enabled){
       for(uint64_t i = 0; i < _total_blocks; i++){     

util.h

@@ -74,7 +74,8 @@ namespace util{
   // This could be implemented using fancy binary arithmatic or builtins, 
   // but this probably suffices if the integer is known at compile time.
   constexpr inline uint32_t log2ceil(uint32_t integer){
-    //return ceil(log2(integer));
+    // I'm doing it this way because log2 is not a constexpr function in the 
+    // Clang toolchain whereas __builtin_clz is.
     return 32u - __builtin_clz(integer - 1u);
   }